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Noiret A., Viblanc V., Bocquet C., Lemmonier C., Lewden A., Robin Jp., Bize P. &Amp; Stier A. (2023). HotPenguin: stress thermique et agressivité soutiennent l’hypothèse température-agression chez le manchot royal en période de reproduction.
Abstract: Les endothermes polaires et subpolaires, adaptés à un climat froid, pourraient se révéler particulièrement sensibles au stress thermique dans un contexte de réchauffement global. L'hypothèse température-agression – qui propose un lien causal entre températures ambiantes élevées et motivation agressive – pourrait accentuer le stress thermique. Essentiellement étudiée pour des raisons socio-économiques, l’hypothèse est peu investiguée chez les espèces sauvages. L’étude de manchots royaux en période de reproduction (n= 85, Crozet), a permis de mettre en évidence des relations positives entre paramètres climatiques (température, radiation solaire), température sous-cutanée, indicateurs comportementaux de stress thermique (halètement, écartement des ailerons) et agressivité envers les congénères. Nos résultats ouvrent de nouvelles perspectives écologiques pour l'hypothèse température-agression, et encouragent l'étude du stress thermique dans les écosystèmes polaires.
Programme: 119
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Olivia Hicks, Akiko Kato, Danuta M. Wisniewska, Coline Marciau, Frédéric Angelier, Yan Ropert-Coudert, Arne Hegemann. (2023). Holding time has limited impact on constitutive innate immune function in a long-lived Antarctic seabird, the Adélie penguin: implications for field studies (Vol. 12).
Abstract: There is great interest in measuring immune function in wild animals. Yet, field conditions often have methodological challenges related to handling stress, which can alter physiology. Despite general consensus that immune function is influenced by handling stress, previous studies have provided equivocal results. Furthermore, few studies have focused on long-lived species, which may have different stress-immune trade-offs compared to short-lived species that have primarily been tested. Here, we investigate whether capture and handling duration impacts innate immune function in a long-lived seabird, the Adélie penguin (Pygoscelis adeliae). We found no evidence for changes in three commonly used parameters of innate immune function upon holding time of up to 2 h, suggesting that immune function in this species is more robust against handling than in other species. This opens up exciting possibilities for measuring immune function in species with similar life-histories even if samples cannot be taken directly after capture.
Keywords: Animals Antarctic Antarctic Regions Ecoimmunology Field study Immunity Spheniscidae Stress
Programme: 1091
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Pauline Douce, Florian Mermillod‐blondin, Laurent Simon, Sylvain Dolédec, Pauline Eymar‐dauphin, David Renault, Cécile Sulmon, Félix Vallier, Anne-Kristel Bittebiere. (2023). Biotic and abiotic drivers of aquatic plant communities in shallow pools and wallows on the sub‐Antarctic Iles Kerguelen (Vol. 46).
Abstract: In the sub-Antarctic region, climate change is particularly rapid, while their freshwater ecosystems, such as ponds, host plant species with limited spatial distributions. These particular systems and their plant communities remain however poorly known and the context of their changing habitat calls for deeper insights into these systems. We performed an extensive survey of 45 ponds over three locations of the Iles Kerguelen during the winter and summer seasons of two years, which included the measurement of 12 abiotic parameters and the assessment of the plant community composition. Overall, our results showed that Iles Kerguelen ponds are shallow freshwater ecosystems harbouring species-poor plant communities with high even- ness, of which structure did not vary among the sampled locations. Three different habitats were identified among ponds in relation with nutrient supply by marine animals, which ultimately influenced plant community structure and cover. We highlight that these habitats are mostly determined by water depth, nutrients, and temperature (mean and variance). Present plant community composition was more strongly correlated with plant community composition in the previous year than with abiotic conditions. Overall, this study provides new knowledge on the aquatic plant communities and the functioning of Iles Kerguelen freshwater ecosystems, which can serve as a basis for future studies dealing with the impact of climate change in the sub-Antarctic region.
Programme: 136
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Pengyang Song, Dmitry Sidorenko, Patrick Scholz, Maik Thomas, Gerrit Lohmann. (2023). The tidal effects in the Finite-volumE Sea ice–Ocean Model (FESOM2.1): a comparison between parameterised tidal mixing and explicit tidal forcing (Vol. 16).
Abstract: Tides are proved to have a significant effect on the ocean and climate. Previous modelling research either adds a tidal mixing parameterisation or an explicit tidal forcing to the ocean models. However, no research compares the two approaches in the same framework. Here we implement both schemes in a general ocean circulation model and assess both methods by comparing the results. The aspects for comparison involve hydrography, sea ice, meridional overturning circulation (MOC), vertical diffusivity, barotropic streamfunction and energy diagnostics. We conclude that although the mesh resolution is poor in resolving internal tides in most mid-latitude and shelf-break areas, explicit tidal forcing still shows stronger tidal mixing at the Kuril–Aleutian Ridge and the Indonesian Archipelago than the tidal mixing parameterisation. Beyond that, the explicit tidal forcing method leads to a stronger upper cell of the Atlantic MOC by enhancing the Pacific MOC and the Indonesian Throughflow. Meanwhile, the tidal mixing parameterisation leads to a stronger lower cell of the Atlantic MOC due to the tidal mixing in deep oceans. Both methods maintain the Antarctic Circumpolar Current at a higher level than the control run by increasing the meridional density gradient. We also show several phenomena that are not considered in the tidal mixing parameterisation, for example, the changing of energy budgets in the ocean system, the bottom drag induced mixing on the continental shelves and the sea ice transport by tidal motions. Due to the limit of computational capacity, an internal-tide-resolving simulation is not feasible for climate studies. However, a high-resolution short-term tidal simulation is still required to improve parameters and parameterisation schemes in climate studies.
Programme: 688
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Pepen Supendi, Nicholas Rawlinson, Bambang Setiyo Prayitno, Dimas Sianipar, Andrean Simanjuntak, Sri Widiyantoro, Kadek Hendrawan Palgunadi, Andri Kurniawan, Hasbi Ash Shiddiqi, Andri Dian Nugraha, David P. Sahara, Daryono Daryono, Rahmat Triyono, Suko Prayitno Adi, Dwikorita Karnawati, Gatut Daniarsyad, Suaidi Ahadi, Iman Fatchurochman, Suci Dewi Anugrah, Nova Heryandoko, Ajat Sudrajat. (2023). A previously unidentified fault revealed by the February 25, 2022 (Mw 6.1) Pasaman Earthquake, West Sumatra, Indonesia (Vol. 334).
Abstract: A destructive earthquake (Mw 6.1) struck Pasaman, West Sumatra, Indonesia, on 25 February 2022, resulting in at least 18 deaths and damage to 1765 buildings. Our relocated foreshock, mainshock, and aftershocks and their source mechanisms reveal a previously unknown ∼20 km long segment of the Sumatran Fault as a result of dextral strike-slip motion (strike N132oE and dip 72oSW) along what we have called the Kajai Fault. The inverted rupture model indicates a single, compact asperity with an approximate depth range of 2–11 km. This asperity extends ∼14 km along strike, and ∼9 km in the down-dip direction. The Coulomb stress change of the mainshock shows that areas to the north and south experienced an increase in stress, which is consistent with the observed aftershock pattern. The nearby Great Sumatran Fault segments (Angkola and Sumpur) experienced a significant increase in stress without any accompanying aftershocks, which likely increases the risk of them rupturing in the future.
Keywords: Earthquake Focal mechanism Kajai Fault Relocation Rupture Stress-change
Programme: 133
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Portier E., Mercier D., Decaulne A. (2023). Schmidt-Hammer Dating of Five Rock Slope Failures in the Westfjords of Iceland.
Abstract: Rock slopes failures (RSF) are numerous in Iceland, especially in the eastern, northern and northwestern regions, which correspond to Tertiary basaltic formations. Five sites have been specifically studied in the Westfjords around Bolungarvík: Óshólar, Minni-Hlið, Sunddalur, Vatnadalur and Meira-Hraun. The aim is to obtain dating of RSF to better understand the chronosequence of post-glacial events. The use of Schmidt-hammer on RSF deposits, consisting in measuring the hardness of the deposited blocks, made it possible to establish relative dating between the different elements of the RSF, and to calibrate datings of the different RSF taking into account carbon-14 dates obtained onto and in the close vicinity of the same landforms, taking benefits of the landform superimposition. For this purpose, macroremains of Betula sp. and paleo-soils were sampled from pits dug in peaty depressions. The SHED results (Schmidt-hammer exposure age dating) thus date the oldest of Óshólar’s RSF to 11,000 cal BP, the Minni-Hlið’s RSF to 9,500 cal BP, that of Sunddalur at 8,700 cal BP, the Vatnadalur one to 8,200 cal BP and finally that of Meira-Hraun at 8,700 cal BP. The chronology of the RSFs dated to the beginning of the deglaciation or the first times of the Holocene therefore fits a paraglacial logic of the emplacement of these deposits.
Programme: 1266
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Portier E., Mercier D., Decaulne A. (2023). Les glissements de terrain dans les Westfjords et les fjords de l'Est d'Islande : inventaire, morphométrie et variables explicatives.
Abstract: Les Westfjords et fjords de l’Est de l’Islande concentrent de nombreux glissements de terrain. Ces phénomènes visibles par observation à distance d’images satellites et d’un Modèle Numérique de Terrain (MNT) ont été inventoriés, puis mesurés et analysés. Au total, 251 et 290 glissements de terrain ont été recensés respectivement dans les Westfjords et les fjords de l’Est, au sein d’une base de données et dans un Système d’Informations Géographiques (SIG). Pour chaque glissement de terrain, sa localisation, sa morphométrie (longueur, largeur, superficie, épaisseur, volume estimé, …), ainsi que de potentielles variables de contrôle, notamment géologiques (lithologie, pendage), ou explicatives (orientation, âge de la déglaciation du versant affecté par le glissement de terrain) ont été relevées. Ces variables et la répartition des glissements ont été étudiées par analyse spatiale et statistique. Ce travail fournit un inventaire complémentaire des glissements de terrain pour ces deux secteurs. Cependant, les facteurs de déclenchement habituellement identifiés ne permettent pas une explication satisfaisante à leur répartition. Néanmoins, des pistes de réflexions se dessinent et l’élargissement de la base de données à l’échelle de l’Islande permet de les comparer d’un secteur à l’autre. Cette étude met en avant des foyers principaux de glissements de terrain : pour les Westfjords, une plus forte densité de glissements de terrain dans le nord-ouest de la zone étudiée et dans la partie la plus étroite de la péninsule ; et pour les fjords de l’Est, une plus forte densité dans le Nord de la zone étudiée. Ces foyers pourraient s’expliquer par les directions d’écoulement de la calotte glaciaire passée. D’autre part, un des constats est une surreprésentation des glissements orientés vers l’ouest et le sud pour les fjords de l’Est, et vers le sud et l’est pour les Westfjords. L’hypothèse proposée est un contrôle climatique : les versants davantage ensoleillés auraient subi une déglaciation plus rapide favorisant l’instabilité des versants. Les données recueillies suggèrent également que la lithologie (basaltes tertiaires) est une variable de contrôle et que la période pendant laquelle la zone de glissement de terrain est déglacée est une variable explicative de l'initiation du glissement de terrain. Les glissements de terrain observés s’inscriraient ainsi dans une dynamique paraglaciaire d’instabilité des versants après la phase de déglaciation
Keywords: Deglaciation Iceland Landslides Paraglacial
Programme: 1266
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Prat R., Dupuis E., Sultan E. (2023). Objets du quotidien en station : l’inventaire comme outil d’analyse des relations.
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Priyashkumar Mistry, Kamlesh Pathak, Aniket Prasad, Georgios Lekkas, Surendra Bhattarai, Sarvesh Gharat, Mousam Maity, Dhruv Kumar, Karen A. Collins, Richard P. Schwarz, Christopher R. Mann, Elise Furlan, Steve B. Howell, David Ciardi, Allyson Bieryla, Elisabeth C. Matthews, Erica Gonzales, Carl Ziegler, Ian Crossfield, Steven Giacalone, Thiam-Guan Tan, Phil Evans, Krzysztof G. Hełminiak, Kevin I. Collins, Norio Narita, Akihiko Fukui, Francisco J. Pozuelos, Courtney Dressing, Abderahmane Soubkiou, Zouhair Benkhaldoun, Joshua E. Schlieder, Olga Suarez, Khalid Barkaoui, Enric Palle, Felipe Murgas, Gregor Srdoc, Maria V. Goliguzova, Ivan A. Strakhov, Crystal Gnilka, Kathryn Lester, Colin Littlefield, Nic Scott, Rachel Matson, Michaël Gillon, Emmanuel Jehin, Mathilde Timmermans, Mourad Ghachoui, Lyu Abe, Philippe Bendjoya, Tristan Guillot, Amaury H. M. J. Triaud. (2023). VaTEST. II. Statistical Validation of 11 TESS-detected Exoplanets Orbiting K-type Stars (Vol. 166).
Abstract: NASA’s Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission designed to find transiting exoplanets orbiting nearby bright stars. It has identified more than 329 transiting exoplanets, and almost 6000 candidates remain unvalidated. In this manuscript, we discuss the findings from the ongoing Validation of Transiting Exoplanets using Statistical Tools (VaTEST) project, which aims to validate new exoplanets for further characterization. We validated 11 new exoplanets by examining the light curves of 24 candidates using the LATTE and TESS-Plot tools and computing the false-positive probabilities using the statistical validation tool TRICERATOPS. These include planets suitable for atmospheric characterization using transmission spectroscopy (TOI-2194b), emission spectroscopy (TOI-3082b and TOI-5704b) and for both transmission and emission spectroscopy (TOI-672b, TOI-1694b, and TOI-2443b). Our validated planets have one super-Earth (TOI-2194b) orbiting a bright (V = 8.42 mag), metal-poor ([Fe/H] = −0.3720 ± 0.1) star, and one short-period Neptune-like planet (TOI-5704) in the hot-Neptune desert. In total, we validated one super-Earth, seven sub-Neptunes, one Neptune-like, and two sub-Saturn or super-Neptune-like exoplanets. Additionally, we identify five likely planet candidates (TOI-323, TOI-1180, TOI-2200, TOI-2408, and TOI-3913), which can be further studied to establish their planetary nature.
Programme: 1066
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Rafael Brahm, Solène Ulmer-Moll, Melissa J. Hobson, Andrés Jordán, Thomas Henning, Trifon Trifonov, Matías I. Jones, Martin Schlecker, Nestor Espinoza, Felipe I. Rojas, Pascal Torres, Paula Sarkis, Marcelo Tala, Jan Eberhardt, Diana Kossakowski, Diego J. Muñoz, Joel D. Hartman, Gavin Boyle, Vincent Suc, François Bouchy, Adrien Deline, Guillaume Chaverot, Nolan Grieves, Monika Lendl, Olga Suarez, Tristan Guillot, Amaury H. M. J. Triaud, Nicolas Crouzet, Georgina Dransfield, Ryan Cloutier, Khalid Barkaoui, Rick P. Schwarz, Chris Stockdale, Mallory Harris, Ismael Mireles, Phil Evans, Andrew W. Mann, Carl Ziegler, Diana Dragomir, Steven Villanueva, Christoph Mordasini, George Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Michael Vezie, Allison Youngblood, Tansu Daylan, Karen A. Collins, Douglas A. Caldwell, David R. Ciardi, Enric Palle, Felipe Murgas. (2023). Three Long-period Transiting Giant Planets from TESS* (Vol. 165).
Abstract: We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single-transit events in the light curves generated from the full-frame images of the Transiting Exoplanet Survey Satellite. Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of M P = 0.30 ± 0.04 M J, a radius of R P = 1.00 ± 0.02 R J, and a low-eccentricity orbit (e = 0.15 ± 0.05) with a period of P = 30.08364 ±0.00005 days. TOI 2338b has a mass of M P = 5.98 ± 0.20 M J, a radius of R P = 1.00 ± 0.01 R J, and a highly eccentric orbit (e = 0.676 ± 0.002) with a period of P = 22.65398 ± 0.00002 days. Finally, TOI 2589b has a mass of M P = 3.50 ± 0.10 M J, a radius of R P = 1.08 ± 0.03 R J, and an eccentric orbit (e = 0.522 ± 0.006) with a period of P = 61.6277 ± 0.0002 days. TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.
Programme: 1066
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